This invention relates to systems for transferring materials into and out of total containment, for example glove boxes. The system relies on the use of sphincter valves which are devices whereby a relatively long and usually smooth and cylindrical casing is passed from one area to another through a series of adjoining ring seals in one direction only so that there is no movement of air, dust or contamination in the opposite direction, unidirectional movement being guaranteed by displacing a casing passing through the seals by another similar casing.